1. Field
An embodiment of the present invention relates to a fuel cell system capable of improving performance and stability by using stack off-gas and an operation method thereof.
2. Description of the Related Art
In this the modern society, there is an increasing concern about environment pollution. As such, there has been active progress in the development of alternative energy such as a fuel cell which is non-polluting and excellent in energy efficiency.
The fuel cell is a device that directly converts chemical energy into electric energy through electrochemical reaction of hydrogen and oxygen. The fuel cell is classified into a polyelectrolyte fuel cell, a solid oxide fuel cell, and a molten carbonate fuel cell in accordance with the electrolyte type. Hydrogen used in the polyelectrolyte fuel cell is typically acquired from a reformate reforming fuel such as methanol, liquid petroleum gas (LPG), gasoline, etc. This fuel is used due to various difficult problems caused by storing and transporting pure hydrogen. Therefore, in most of fuel cell systems using a steam reforming type reformate, a heating unit supplying heat required for steam reforming reaction is provided in the reformate.